Safety arrester cables, in the state of the art are applied where rigid connections are to be able to destroyed under certain conditions, and it is to be ensured that the part which has broken away may not fly off in an uncontrolled manner and on account of this create damage or endanger people.
In motor racing sport it is often the case that with collisions of two vehicles, or of a vehicle with the bordering of the racing track, the wheel axles and their suspension break, and the wheel flies off in an uncontrolled manner or is catapulted away. People at the edge of the racing track have often been injured or even killed by way of this. This problem is known and safety regulations have been imposed to the extent that the wheels must be connected to the body of the vehicle via a safety arrester cable. Until now many grave accidents have been avoided by way of this safety precaution, but despite this, the safety arrester cables applied until now still have an insufficient effect.
On the market today there are fibres or yarns manufactured from these which have a tear strength which is a multiple greater than that of steel fibres. Whilst for example steel fibres have tear strength of 3.0 cN/ dtex, carbon fibres have tear strength of 20 cN/ dtex. The relatively elastic m-aramide fibres also have a tear strength of 4.7 CN/dtex, whilst the rigid p-aramide fibres have a tear strength of 19 CN/ dtex and modern PBO fibres even have tear strength of about 37 cN/dtex. Safety arrester cables which are manufactured from these modern highly tear-resistant fibres, such as carbon fibres, p-aramide fibres and PBO fibres are capable of accommodating tensile forces which indeed far exceed the forces which actually occur.
Accordingly such safety arrester cables have been manufactured of corresponding highly tear-resistant fibres, wherein the corresponding yarns of such highly tear-resistant fibres have been endlessly wound between the two end attachment eyes. The corresponding fibres as a result of this all run parallel to one another. With regard to those accidents which were investigated, one could ascertain that the cable stood up to the forces occurring between the two attachment eyes, whilst it was the attachment eyes which were broken. The construction of such a safety arrester cable according to the state of the art is shown in FIG. 6. The actual cable A is shown in FIG. 6. The actual cable A is manufactured of several endlessly wound loops B and runs through an attachment eye C which here is shown merely schematically. A shrinkage sleeve D is attached over the cable A. As already mentioned, the occurring breakages have always been ascertained at the attachment eye. This is not very surprising since the highly tear-resistant materials usually have an extension up to the breakage extension of 1.5 to maximally 3.5 percent. This in principle could also be compensated by way of manufacturing a correspondingly long safety arrester cable. This however cannot be done since on account of this there exists the danger that the wheel which is attached to the arrester cable could impact the driver. Added to this is the fact that it is indeed in motor racing sport that an as light as possible safety arrester cable with an as low as possible air resistance is desired. Thus it is no solution to manufacture the safety arrester cables of a less high-strength but more elastic material and to design the cable accordingly thicker.
The problem may only be solved by way of observing the cable and the attachment eye as a coherent system, wherein this system must have the best possible work-to-break-energy.
In one article, E. R. Barron “Hybrid Tyre Cords Containing Kevlar Aramid” (Kautschuk+Gummi·Kunstoffe, Vol. 40, 1987, No. 2, pages 130–135) describes the advantages of three-ply so-called hybrid cables which are manufactured from combinations of aramide with nylon, polyester or other textile yarns. Such hybrid yarns compared to pure yams have an improved elasticity and an increased resistance to fatigue breakage. These facts have been realised in tyre manufacturing technology, not only in motor racing.
It is therefore the object of the present invention to improve a safety arrester cable of the initially mentioned type such that the work-to-break-energy of the whole system of the safety arrester cable is significantly increased and thus a danger of a breakage of the safety arrester cable may be significantly reduced.